New opt-in feature for less stalemates in CA when round timer runs out

New opt-in feature for less stalemates in CA when round timer runs out
New cvar: `g_ca_prevent_stalemate 0|1`
First the amount of players alive in each team is checked, if there is a single highest then that team wins the round.
If two teams have the same amount of players then their total health counts are calculated and compared.
If there is the same amount of players and total health in the 2 top teams then it's still a stalemate.

Code cleanup by z411